Pathfinder was originally built by people who didn't like the more streamlined direction that d&d was going in. So if you played baldur's gate and thought that the game could use more options and added complexity, Pathfinder's the direction you'll go in. If you found the systems already too complex or annoying to internalize and manage, modern d&d has that taken care of for you.
"History Is Much Like An Endless Waltz. The Three Beats Of War, Peace And Revolution Continue On Forever." - Gundam Wing: Endless Waltz